The order Nautilida belongs to theclass of Squid-like animals(Cephalopoda) and phylum of Molluscs(Mollusca). The nautilus is a cephalopod whose"siphoning" (pipe) is located in the center of the chambers and a generally very involute shell. The animal can rise and decent in the water column by pumping more or less water in its chambers.

The"suture lines" (line separating the rooms) are less complex in shape than ammonites. The group appears in the fossil record from the early Devonian. The genus Nautilus has a limited number of recent representatives, most notably the N. pompilius, which occurs in the ocean near Madagascar.